Heat exchanger



Sept. 14, 1948. J. w. BROWN, JR 2,449,052

HEAT EXCHANGE!! Filed Jan. 13. 1945 42 sheets-sheet 1 Spt. 14, 1948. J, w, BROWN, JR 2,449,052

HEAT EXCHANGER 2 Sheets-Sheet 2 Filed Jan. 13, 1945 Illllm mmm? w .NWN

Patented Sept. 14, 1948 UNITED STATES PATENT OFFICE HEAT EXCHAN GER John W. Brown, Jr., Lakewood, hio, assignor to Brown Fintuhe Company, Elyria, Ohio, a corporation of Ohio Application January 13, 1945, Serial No. 572,627

4 Claims. (Cl. 285-20) 2 This invention relates to'tubular connections inner-tube connection and the connection beand more particularly to connections or fittings tween the inner and outer tubes of the heat exfor joining two tubes or pipesof different diamchanger; Figure 5 is a detail view, partially in eters. The connections or fittings are especially cross-section, of the portion of the apparatus useful in heat exchangers, but it is to be under- 5 of Figure 4 to the left of the plane 5 5; Figure stood that they may be employed for other pur- 6 is a detail view, partially in cross-section, of poses. the portion of the apparatus of Figure 4 to the left A general object of the invention isto provide of the plane 6 6 of Figure 4; and Figure '7 is an an eilicient connection for joining tubes of dlilerenlarged longitudinal sectional detail view subent diameters, which can be manufactured at 10 stantially corresponding to Figure 4, representing relatively low cost and which will withstand exthe tube connections cut as indicated by line 1 1 tremely high pressures without leakage. Another of Figure 2. The corresponding sectionalized object is to provide such a connection which readportion oi Figure 1 is also represented as being ily can be assembled or disassembled without recut as indicated by line 1 1 of Figure 2. Like quiring any special tools or equipment. Another reference characters are utilized throughout the object is to provide such a connection, particudrawing to designate like parts.

larly for concentric tubes. in which no substan- In the drawings I have illustrated a heat extial torsional forces are placed on either the inchanger designed to employ my preferred form ner. tube or the outer tube by the operations of of tubular connection. This heat exchanger is connecting and disconnecting the connection. A of the hairpin type and comprises an inner hair further object is to provide an eillcient and pin or U-tube indicated generally at IU and made economical heat exchanger embodying such a tuup of two straight portions II and I2 connected bular connection. by a return bend I3, preferably welded to vthe Another object is to provide a novel flanged straight portions as indicated at I4, although head seal and flanged union, eliminating screw unions or other means for connecting the repipe fittings and screw pipe unions. turn bend and the straight portions may be A further object is to provide a tube connec.- employed if desired. Shell tubes I5 and I6 surtion vemploying gasketed seals, and eliminating round the straight portions Ii and I2 of the hairground joints and all maintenance troubles compin tube I0. In order to increase the rate of mon to ground joints. An additional object is 3i interchange of heat between the commodity withto provide a construction in which the gaskets in the tubes I I and I2 and the COmmOdiy S111- are renewable and fully retained, and wherein rounding these tubes and within the shell tubes the joints may be inspected easily before seall5 and I6. the straight portions II and I2 are ing. preferably provided with fins I1 constructed in Still another object is to provide a heat exaccordance with the teachings of my prior Patchanger connection in which seals may be made ents NO- 2.261.136 and N0. 2,251,137-

or broken with a small standard wrench, from The tubes Il and I2 are Provided at their outer the front, permitting close side-by-side installa- 0r exposed ends with connections or fittings intion 0f units in minimum Space, dicated generally at I8 and I9 by means 0f Which Still another object is to provide a substan 4Q inlet and outlet pipes 2U and 2|. 0r COIlneCting tially unitary compact fitting construction for pipes may be Sealed to' the inner tubes Il and sealing an inner tube to an outer tube and also l2 respectively. The fittings I8 and I9 serve in sealing the inner tube to a connecting pipe. addition to connect theinner tubes to the outer Further objects/and advantages 0f the inven- .tubes as Will be explained in greater detail heretion will become apparent from the following de- .illefter- If the exchanger is designed for counscriptionv of a preferred form/thereof, reference telOW Operation the Other Commodity may be being madeto the accompanying drawings in i supplied to the interior of the shell tube I6 which Figure 1 is an elevation partly in section through the inlet pipe 25 Welded t0 the shell tube showing a double tube heat exchanger made ac- RS ShOWIl at 26 and provided at its end with a cording to my invention: Figure 2 is a front ele- 50 conventional flanged connection as at 21. Fluid vation of the heat exchanger shown in Figure 1; Supplied through the inlet 25 flows in the direction Figure 3 is a rear elevation with parts broken of the arrows to the rear end of the exchanger away. showing the heat exchanger of Figure 1; where the tube I6 is connected to the tube I5 by Figure 4 is anenlarged exploded view representmeans of a connecting member 28 welded to the ing-'in longitudinal section the elements of the 55 ends of the tubes as indicated lat 29 and 30,

3 and a plate 3| welded to the tubes and to the member 28. A removable cover plate 35 is secured by bolts 36 to the flange 31 which is welded to the member 28. One of the bolts, indicated at 36a, preferably provided with a reduced-diameter, headed extension 36h thus providing a pivotal support whereby the cover plate can be pulled out of engagement with the other bolts, and then swung about the bolt 36a as a pivot to give access to the interior of the exchanger. The cover plate may be secured in displaced position by one of the bolts 36 adjacent the bolt 36a. A suitable gasket 38 may be provided between the cover plate and the flange in order to make a leak-proof connection. Thus fluid may iiow to the rear of the heat exchanger through the tube I6 around the outside of the return bend I3 and into the tube I5, thence within the tube I to the outlet pipe 39 which, like the inlet pipe 25, is provided with a conventional flanged union 48. With such an arrangement, counterflowof the commodities in the inner and outer tubes will take place. If desired, concurrent ow may be obtained merely by reversing the inlet and outlet connections for either the inner tube or the outer tubes. Several exchangers may be connected together in series if desired, and may be supported by brackets 4I and 42.

One of the fittings I8 and I8, which I provide for making the necessary connection between the ends f the shell tubes l5 and I6 and the legs II and I2 of the hairpin tube, is shown on an enlarged scale in Figures 4 and '1. The connection between the shell tubes and the hairpin tube must be leakproof under high pressures and widely varying temperature conditions, must accurately position the tubes with respect to each other, and must be designed so that it can be assembled and demounted without difficulty. These and other advantageous results I attain by providing in each fitting or connection, e. g. in the fitting I8, an end flange 45 for the outer tube I5, an enlarged end or flange 46 for the inner tube II, a sealing ring 41, a split locking ring 48, and clamping or securing studs or screws 48. For enabling the same fitting I8 to seal the connecting pipe 20 to the inner tube II, I provide therein a clamping ring 5I, securing means such as studs or screws` 52, and an end member 53 for the connecting pipe 28, having a collar 54.

The end flange 45 of the outer tube I5 may be integral with the remainder of the tube I5, but is preferably welded thereto as shown at 55. Sirnllarly the enlarged end portion or flange 46 of the inner tube II may be integral with the remainder of the tube II, or may be a separate piece welded thereto as shown at 56 to form a unitary construction. The split locking ring 48 is provided for locating the tube Il concentrically within the outer tube I5 and, also, for the purpose of preventing longitudinal motion of the tube II into the tube I5 when the sealing ring 4'1 is to be drawn against the sealing surfaces of the tubes. To this end the outer tube I5 is counter-bored within the end portion of the flange 45 to provide an enlarged inner-diameter portion 51 fitting the outer surface 58 of the split locking ring 48, and to provide an outwardly facing shoulder 58 against which the surface 68 of the ring 48 is adapted to bear. Furthermore, the enlarged end portion 46 of the inner tube II is provided with a cylindrical portion 6I having such an outer diameter as to t within the inner surface 62 of the split locking ring 48 and is provided with a back surface 4 or inwardly facing shoulder 63 adapted to bear against a surface 64 of the split locking ring 48.

Preferably the end portion 46 of the inner tube II is grooved so that the cylindrical surface 6I forms the bottom of an annular groove adapted to receive the inner edges of the split locking ring 48 for holding it more conveniently when the connection is being assembled or disassembled. Furthermore, in order to provide for more convenient assembly, the locking ring 48 is preferably also counter-bored so that the surfaces 64 form an inner shoulder, and a larger inner-diameter portion 65 is provided, adapted to fit the outer surface 66 of a portion of greater diameter in the end 46 of the inner tube Il. In this manner the split locking ring 48 is provided with what may be called an L-shaped cross-section in which the leg portion of the L along the surface 65 lies between the inner surface 51 of the counter-bore in the outer tube I5 and the outer surface 66 of the end portion of the inner tube II.

In order to avoid the necessity for a ground joint, a gasket 61 is preferably provided, which is adapted to form a seal between the end surface 88 of the flange portion 45 of the outer tube I5 and the end surface 1I of the end portion or member 46. In order to receive the gasket 61 and to increase the ease of assembly, the end of flange 45 is preferably counter-bored to form a recess 12. The sealing ring 41 is similarly set back as at 13. The gasket may be of any conventional material, or if desired a ring of metal, such as soft iron, may be urged against annular sealing surfaces on either side of the clearance space 13a. The sealing surfaces 88 and 1I on the outer and inner tubes, respectively, are preferably disposed in substantially the same plane, adjacent the ends of the respective tubes (the word adjacen being used here and in the claims to mean that the sealing surfaces are at or near the ends of the tubes).

The sealing ring 41 and the flange 45 are provided with appropriate holes 14 and 15, respectively, for receiving the bolt or screw means 48. Preferably, however, the holes 15 in the flange 45 are threaded in order that the securing means 48 may take the form of studs, provided with suitable nuts 48a as shown. Ordinarily the nuts are employed in the assembly and disassembly of the joint, the studs remaining fixed except when they require replacement because of wear or damage. For reasons which will immediately appear, however, not all of the holes 14 and 15 have the studs 48 passing through them. In the specific arrangement shown by way of illustration thereare eight such holes and only four screws and nuts are employed for clamping the sealing ring 41 against the gasket 51.

The clamping ring 5I is fitted around the neck 16 of the end fitting or portion 53 of the connecting pipe 20, and the end surface 11 thereof is adapted to fit against the end 46 of the inner tube II to form a seal, preferably a gasketed seal in order to avoid the necessity for ground joints. The arrangement is such that the collar or enlargement 54, which is preferably integral with the end fitting 53, which lies between the end sealing surface 11 and the clamping ring 5I. In order that the clamping ring 5I may be placed around the neck 16 of the connecting pipe 28 without employing a split ring construction, it is preferable to utilize an originally separate portion 53 to form the end of the connecting pipe 28 and to join it to the remainder of the connecting tube 2l by means of a weld, as shown at 16, after the ring 5I has been slipped over the neck 16. In this manner it is possible to form the connecting pipe with an elbow or to utilize return bends in case it is desired to use a bank of heat exchanger units.

In order to secure the clamping ring 5I. I preferably employ the longer studs or screws 52, which are adapted to pass through openings 19 in the clamping ring 5I, through the remaining openin-gs 14 and 15 in the sealing ring 41 and the flange 45 of the outer tube I5 respectively. The four screws 52 are threaded into the openings 15 in the ange 45 which are not occupied by the shorter studs 45 serving to secure the sealing ring 41, and nuts 52a are employed to clamp the ring 5I. In order to give access to the shorter cap screws 49, the ring 5I is preferably formed with ears 5I, leaving spaces 82 between the ears exposing the nuts 49a.

Although the entire end surface of the end portion 46 of the inner tube I I may be in a single plane, enabling a single gasket tovseal the connection between the inner and outer tubes and also to seal the connection between the inner tube I I and the connecting pipe 20, I consider it preferable to machine the end portion 46 of the inner pipe II so as'to form a recessed portion 83 having suitable diameter to receive the end 11 of the end member 53 of the connecting pipe 2i), and to receive a separate gasket 85 for sealing the joint between the inner tube II and the connecting pipe 20, thus avoiding damage to the gasket 61 in case the connecting pipe and the inner tube are to be disassembled without disassembling the inner tube and the outer tube. Furthermore, the recess 63 serves to retain the gasket 85. In order to provide a sturdier connection, the portion 56 of pipe 20 preferably has a greater outside diameter than the remainder of the connecting pipe 26.

It is to be observed that no screw pipe fittings or unions whatsoever are required so that there is no danger of subjecting any of the tubes or pipes to torsion during the assembly or disassembly operations regardless of the experience or carefulness of workmen performing the operation. Furthermore, since no such screw pipe llttings are required, which necessarily have large diameter nuts, it is unnecessary to use any longhandled wrenches; and simple standard short handled spanners may be employed for making or breaking the seals between the inner tube and the connecting pipe, and between the inner and outer tubes. The avoidance of the necessity of such long-handled wrenches greatly increases the compactness of the assembly since it is unnecessary to provide suilicient clearance space between the pipes 20 and 2|, between the tubes II and I2, and between the tubes I4 and I5 to permit use of long-handled wrenches. Furthermore, it is unnecessary to allow great space between separate heat exchanger units in case a bank of such units as illustrated in Figure 1 is to be employed.

As noted above there are two separate seals, namely, one seal between the inner tube II and the connecting pipe 20, and the other seal between the inner tube II andthe outer tube I5. Each of these seals may be made or broken independently of the other. Thus when the entire apparatus is to be assembled with the parts arranged as shown in Figure 4, the seal between the inner and outer tubes may be tightened rst by separating the halves of the split locking ring 4l and placing the portions 62 in the annular groove 6I of the end portion 46 of the inner tube II. causing the split locking ring 48 to slide into the counter-bore 51 of the outer tube I5 until the surfaces 5B and 58 come into abutment, limiting further inlward motion of the inner tube II. Thereupon, the sealing ring 41 may be drawn against the gasket 61 by means of the nuts 45a. The seal between the inner pipe II and the connecting pipe 20 may then be made by placing the gasket in the recess 63 of the inner tube II, and clamping the end surface 11 of the connecting pipe 20 against the gasket 55 by means of the nuts 52a. Since the split locking ring 45 serves to limit inward motion of the inner tube I I within the outer tube I5, the nuts 52a serve to draw the sealing surface 11 of the connecting pipe 2l against the sealing surface 53 of the inner tube II although the cap screws 52 are not directly connected to the inner tube Il. It may be observed that the sealing ring 41, having an opening 81 adapted to receive the portion l5 of the connecting pipe 20, senves to center the end of the connecting pipe with respect to the end of the inner tube.

If for any reason it'should be desired to tighten the seal between the inner tube II and the connecting pipe 20 before the seal is tightened between the inner and outer tubes, the nuts 52a may be drawn up before the nuts 49a.

The apparatus may be disassembled by carrying out the operations in reverse manner. Thus when the nuts 52a have been removed and the inner tube I I has been moved to the right a short distance, the halves of the locking ring 48 will be separated, enabling the inner tube II to be moved to the left for disassembly of the complete apparatus by removing the inner tube Il if desired. Obviously, when a hairpin tube as shown in Figure 1 is employed, the connection with the shell tube at the end of the tube I2 should be made or broken at the same time as the similar connections for tube II.

In the particular heat exchanger shown, the hairpin tube can then be removed from the two shell tubes by swinging the cover plate 35 to one side, using the bolt 36a as a pivot. Then the hairpin tube can be pulled out of the two U-tubes through the opening at the rear of the exchanger made by removing the cover plate 35. In exchangers fwherein the return bend of the hairpin tube is connected to the straight portions thereof by couplings or unions, then if desired the straight portions of the hairpin tube can be separately removed from the shell tubes by disconnecting them from the return bend, breaking the connection between the shell tubes and the straight portions as described above and pulling the tubes outwardly from the frontend of the exchanger, i. e., to the right in the drawing. Thus my fitting or connection is adapted to heat exchangers of various types as well as being useful in other environments where it is desired to connect tubes or pipes of different diameters.

As explained above, my fittings may be tightened or loosened merely by tightening or loosening the relatively small nuts on screws 49 and 52. The elimination of large nuts and unions makes possible a compact construction and greatly increases the ease of assembly and demounting. Only small wrenches are required. Thus no severe torsional strains or stresses can be placed on either the shell tube or the fin tube in the operation of tightening the joint, nor is either The tube II is then moved toward the left..

7 tube placed under compression or tension in making the joint. The hairpin tube is held xedly in proper position with respect tothe shell tubes by the connection, yet the tube is free to expand and contract under the inuence of temperature changes without placing any strain .upon the connection. The gaskets can be replaced readily when necessary and the sealing surfaces can be inspected and cleaned immediately before the gasket Iand sealing ring are placed in position. The parts are shaped so that they can be formed and machined at relatively low cost and with ordinary production methods.

Those skilled in the art will appreciate that various changes and modifications can be made in my invention without departing from the spirit or scope thereof. It is therefore to be 'understood that my patent is not limited to the preferred form of my invention described herein, or any manner other than by the appended claims.

I claim:

1. In a heat exchanger embodying an outer tube and an inner tube adapted to join a connecting pipe, means for connecting the inner tube to such a pipe and to the, outer tube comprising an outwardly facing shoulder near the end of the outer tube, an enlarged end on the inner tube having a maximum diameter less than the minimum diameter of the outer tube and providing an inwardly facing shoulder near the end of the inner tube, interlocking means adapted to engage between the shoulder of the outer tube and the shoulder of the inner tube for limiting inward movement of the inner tube in the outer tube, a sealing surface adjacent one end of the outer tube, a sealing surface on the enlarged end of the inner tube, a sealing ring adapted to seal against the sealing surfaces of both said tubes, said connecting pipe having a sealing surface adjacent one end thereof, means connected to said outer tube for drawing said sealing ring simultaneously against said inner and outer tube sealing surfaces, and means connected to said outer tube for drawing the connecting pipe into sealing engagement with the inner tube.

2. A union for connecting inner and outer concentric tubes and for connecting a connecting pipe to the inner tube, comprising an outwardly facing shoulder near one end of the outer tube, an inwardly facing shoulder near one end of the inner tube, a split locking ring adapted to fit between the shoulder of the outer tube and the shoulder of the inner tube for limiting inward movement of the inner tube in the outer tube, a sealing surface on the outer tube, a sealing surfaceon the inner tube disposed adjacent the sealing surface. on the outer tube, a sealing ring adapted to seal against the sealing surfaces of both said tubes, the connecting pipe having a sealing surface adjacent one end thereof, means connected to the outer tube for drawing said sealing ring simultaneously against said inner and outer tube sealing surfaces, and means connected to the outer tube for drawing the connecting pipe into sealing engagement with the inner tube.

3. A union for connecting inner and outer concentric tubes and for connecting a connecting pipe to the inner tube, comprising an outwardly facing shoulder near one end of the outer tube. an inwardly facing shoulder near one end of the inner tube, a split locking ring adapted to flt between the shoulder of the outer tube and the shoulder of the inner tube for limiting inward movement of the inner tube in the outer tube, a sealing surface on the outer tube, a sealing surface on the inner tube disposed adjacent the sealing surface on the outer tube, a sealing ring adapted to seal against the sealing surfaces of both said tubes, the connecting pipe having a sealing surface adjacent one end thereof, .the outer tube having yan outwardly extending flange, screw means engaging said flange and said sealing ring for drawing said sealing ring simultaneously against said inner and outer tube sealing surfaces, and screw means engaging said flange and passing through openings in said sealing ring for drawing the connecting pipe into sealing engagement with the inner tube.

4. A union for connecting inner and outer concentric tubes comprising an outwardly facing shoulder near the end of the outer tube, an enlarged end on the inner tube having a maximum diameter less than the minimum diameter of said outer tube and providing an inwardly facing shoulder near the end of the inner tube. a split locking ring adapted to engage between the shoulder of the outer tube and the shoulder of the inner tube for limiting inward movement of the inner tube in the outer tube, a sealing surface adjacentone end of the outer tube, a sealing surface on the enlarged end of the inner tube, a sealing ring adapted to seal against the sealing surfaces of both said tubes, and means connected to said outer tube for drawing said sealing ring simultaneously against said inner and outer tube sealing surfaces.

JOHN W. BROWN, Jn.

'REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,497,652 Browne June 10, 1924 1,869,739 Dean et al. Aug. 2, 1932 2,087,179 Barker July 13, 1937 

